Commercial and/or industrial electrical panel meter systems may provide electrical power and circuit-breaker protection to a plurality of electrical branch circuits via an electrical panel coupled to a power source. Commercial and/or industrial electrical panel meter systems may have, e.g., 40-50 branch circuits. Each branch circuit may have its own meter module mounted in the electrical panel that may provide electrical data readings at periodic intervals as determined by a controller of the electrical panel meter system. The electrical data readings may include one or more of, e.g., power (kilowatts), power per unit of time (kilowatt-hours), voltage (volts), current (amps), power factor, etc., and/or related parameters and combinations thereof. In some known electrical panel meter systems, the controller may sequentially command each of the meter modules to sample and transmit back to the controller respective electrical data readings. Cycling though all of the meter modules may require a total of, e.g., 10 seconds, as each meter module reads and transmits its electrical data back to the controller. Each electrical data reading is typically not timestamped. After the controller receives the electrical data readings from all of the meter modules, the electrical data readings may be stored in a memory at the electrical panel or uploaded to a host computer. In each case, a timestamp may be generated. However, such a timestamp representing a relatively large span of time (e.g., the 10 seconds) over which all of the electrical data readings were taken may not be suitable for high accuracy power quality analyses commonly performed on one or more branch circuits in a commercial and/or industrial electrical system. Such high accuracy power quality analyses may require each electrical data reading timestamp to have, e.g., millisecond resolution.
Accordingly, there is a need for apparatus and methods for timestamping each electrical data reading performed by each meter module in an electrical panel meter system.